explain cmos technology?

Answer 1

How deep do you want to go

cmos + capacitive Mosfet

the Mosfet was an advancement on the igfet technologies of late 70s early 80s

igfet = insulated gate fet

fet = field effect transistor (different to the earlier bipolar transistor)

Answer 2

Here are a couple of links:
http://www.dalsa.com/markets/ccd_vs_cmos.asp
http://www.shortcourses.com/how/sensors/sensors.htm